Early functional languages were based on two basic constructs:

  *Linked lists (cons-cells) for data structures
  *Recursion (with or without TCO) for control flow

Both of these concepts are fundamentally sequential and not less important very low level. For today's manycore/parallel/distributed world, better fit would be:

  *Nested data-parallel types (like in NESL or Intel ArBB)
  *HOFs, array/dictionary/parallel comprehensions